Motor-driven apparatus for cleaning spaces between teeth by dental floss

ABSTRACT

Motor-driven apparatus for cleaning spaces between teeth by dental floss comprising a dental floss for cleaning the spaces between teeth, motor means (11), a feeding reel (24) of the fresh dental floss, a take-up reel (25) of the worn-out dental floss, a set of pulleys (18, 20, 21A, 21B) about which the dental floss is running between feeding reel and take-up reel, and reciprocating motor means (13, 15, 16, 18) to reciprocate the operating length of the dental floss as well as to keep it stretched and to replace the dental floss as it is worn-out.

This invention relates to a motor-driven apparatus for cleaning spacesbetween teeth by dental floss comprising a dental floss for cleaning thespaces between teeth, motor means, a feeding reel of the fresh dentalfloss, a take-up reel of the worn-out dental floss, a set of pulleysabout which the dental floss is running between feeding reel and take-upreel, and reciprocating motor means to reciprocate the operating lengthof the dental floss as well as to keep it stretched and to replace thedental floss as it is worn out.

As known, in order to prevent tooth decays and swollen gums it is veryimportant to keep the spaces between teeth strictly clean.

At present there are commercially available dental flossessatisfactorily performing their cleaning function by the introductioninto each space between adjacent teeth and the reciprocation caused bypulling and releasing the dental floss stretched between the left handand the right hand of the user.

There are also available fork frames to be used by hand and havingprongs between which a floss is stretched and moved like a reciprocatingsaw.

Such fixtures besides being efficient only when used by care andpatience are not suitable for a rational use of the dental floss, somelengths of which are not conveniently exploited.

On the other hand, in the field of tooth and gum cleaning the problemsof an irrational use of the tooth-brush have been almost solved by thecommercially available motor-driven tooth-brushes. Therefore theapplicant has sought to provide a motor-driven apparatus for therational use of the dental floss for cleaning the spaces between teeth.

To this end the applicant has devised an apparatus comprising asmall-size casing to be introduced into the mouth and in which a lengthof dental floss is exposed to the outside through an opening, and meansable both to reciprocate such a length of dental floss and to feed itstep by step so that it can be replaced by fresh floss as it isworn-out.

In this field document U.S. Pat. No. 4,245,658 discloses an automaticflossing apparatus which stores the dental floss, holds it automaticallyunder tension and agitates and renews the floss during itsmanipulations. The floss unwinds from one spool and rolls on anotherautomatically. The floss makes a complete circuit passing by anoscillator imparting back and forth movements to the floss andsubsequently to a two-pronged headpiece holding the floss under tensionacross the two prongs. The spools are connected by a clutch and cranktransmission mechanism which maintains controllable floss tension.

The construction of the apparatus is extremely complicated and requiresa very large number of component parts cooperating together to performits function.

The oscillating action is caused by the motor, the shaft of which isoscillating due to the utilization of a cam. The circuit followed by thedental floss is very long and involves a great deal of bends around anequal number of guide members with the danger of tangling. Furthermorethe spools are connected by a complicated transmission mechanismcomprising a crank, a belt, biassing and subtension springs and pressurewheels.

As it will be self evident this construction, besides being verycomplicated and consequently expensive, seems to be likely to raiseoperation problems.

The present invention will be now described into detail with referenceto the annexed drawing, in which:

FIG. 1 is a somewhat schematic view of an embodiment of the apparatus inlongitudinal section to show the internal mechanism in one position ofthe reciprocated connecting rod;

FIG. 2 is a similar view of the apparatus with the connecting rod in adifferent position;

FIG. 3 is a fragmentary section in enlarged scale showing anotherembodiment with handle and casing separated from each other and afeasible cluth device; and

FIG. 4 is a detailed view of the pulleys stretching the dental floss andthe reciprocated double pulley.

With reference firstly to FIGS. 1 and 2 the apparatus according to theinvention comprises a casing 10; a motor 11 provided with reduction gearand helical driving gear 12; a first gear wheel 13 of small diametermeshed with gear 12 and idle-mounted on casing 10; a second gear wheel14 of greater diameter also idle-mounted in casing 10 and meshed withthe first gear wheel 13; a connecting rod 15 driven by the first gearwheel 13 by means of a crank 16 integral with the latter; a first pulley18 mounted at the end 19 of the connecting rod 15; a second pulley 20idle-mounted in casing 10 and facing pulley 18, and a pair of freepulleys 21A, 21B idle-mounted in the head 22 of casing 10 at both sidesof opening 23.

The apparatus further includes a feeding reel 24 of the fresh dentalfloss and a take-up reel 25 of the worn-out dental floss. It should benoted that the take-up reel is integral with the second gear wheel 14,while the feeding reel in this embodiment is coaxially mounted with theassembly formed of the second gear wheel and the take-up reel with theinterposition of a clutch device, as shown in the embodiment of FIG. 3.

For a fully understanding of the description, floss FL, cleaning thespaces between teeth and extending from feeding reel 24 to take-up reel25 around several pulleys as described herebelow in greater detail, isdivided in several lengths, each of them extending from a pulley to thenext one. Therefore the first length between feeding reel 24 and pulley20 is designated by 30; the second length between pulley 20 and doublepulley 18 is designated by 31; the third length between pulley 18 andpulley 21A is indicated at 32; the length between pulley 21A and pulley21B is indicated at 33, the latter being the operating length; thelength between pulley 21B and pulley 18 is indicated at 34; and finallythe length between pulley 18 and take-up reel 25 is designated by 35(FIG. 4).

As known the active length of the dental floss for cleaning spacesbetween teeth should be reciprocated in the apparatus of this inventiondue to the rotation of pulley 18 mounted at the end 19 of the connectingrod 15.

To this end the clutch device mounted between feeding reel 24 and itssupport member is mandatory.

In operation, motor 11 rotates gear wheel 13 which reciprocates throughcrank 16 the double pulley 18 approaching and moving away from pulley20, as shown in FIGS. 1 and 2.

Since length 30 of dental floss FL is held by clutch device 38 (FIG. 3)this relative movement of double pulley 18 causes length 33 stretchedbetween the freely rotating pulleys 21A and 21B, to run with respect towindow 23. It should be appreciated that the pulleys are arranged suchthat length 33 is shifted in both direction by a double as high extentthan that of the reciprocated pulley 18 due to the so called chainpulley effect (FIG. 4).

As for the details of this movement it should be noted that thereciprocation of central floss length 33 is caused by the alternatevariation of the length of the floss loops formed of lengths 30, 31 andlengths 34, 35, respectively.

It should also be appreciated that the rotation of gear wheel 13 causesalso gear wheel 14 to be rotated even if much more slowly due to thetooth ratio of the gear wheels.

The rotation of gear wheel 14 likewise causes take-up reel 25 to berotated (FIG. 3), thus pulling the dental floss in one direction by agreater force than that of the clutch device 38 in the oppositedirection, so that dental floss FL is unwound a little at time fromfeeding reel 24. Thus the dental floss of the operating length 33 iscontinuously replaced by fresh floss, the worn-out floss being wound ontake-up reel 25.

The movement of the floss from feeding reel 24 to take-up reel 25 isdesignated by arrows along the path of the dental floss indicating alsothe reciprocation of the operating length 33 and the adjacent lengths.

In the embodiment of FIGS. 1 and 2 the motor and the housing of thecells (not shown) are located in the handle 40 of the casing 10.

In FIG. 3 a second embodiment is shown in fragmentary exploded section,in which casing 110 and handle 140 are separated and adapted to befitted by snap means of known type (not shown). In FIG. 3 a clutchdevice 38, adapted to be included also in the embodiment of FIGS. 1 and2, is also shown in detail.

Clutch device 38 is provided with friction felt 42 placed between theone-piece assembly of gear wheel 114/take-up reel 125 and feeding reel124 coaxially mounted on pin 143.

Handle 141 and casing 110, the latter being of disposable type and beingreplaced when all of the dental floss is passed from feeding reel 124 totake-up reel 125, are connected by snap means of known type which arenot further described. However, the coaxial arrangement of the two reels24 (or 124) and 25 (or 125) with the gear wheel of larger diameter 14(or 114) should be appreciated.

Of course, in the embodiment of FIG. 3 some parts have a differentconstruction from the embodiment of FIGS. 1 and 2, even if they have thesame function of transmitting the movement of motor 111 to gear wheel113 carrying crank 16; among them there is in particular the coupling ofkey pin 145 of the latter into the cavity of gear 112 driven by motorshaft 146.

I claim:
 1. Motor-driven apparatus for cleaning spaces between teeth bydental floss (FL) comprising an outer casing (10) provided with handle(40), a dental floss (FL) for cleaning the spaces between teeth, anelectrical motor (11), a feeding reel (24) of the fresh dental floss, atake-up reel (25) of the worn-out dental floss, a set of stationarypulleys (20, 21A, 21B) around which the dental floss is running betweenthe feeding reel (24) and the take-up reel (25), and reciprocating drivemeans (13, 15, 16) to reciprocate the operating length (33) of thedental floss (FL) as well as to keep it stretched and to replace thedental floss as it is worn-out characterized in that said electricalmotor continuously rotating, drives reciprocating driving means (13, 15,16, 18) for reciprocating said operating length (33) of the dentalfloss, comprising a first gear wheel of small diameter (13) mounted onsaid casing (10) and meshing with a gear (12) mounted on a shaft of saidelectrical motor (11); a crank (16) operated by said small gear wheel(13), a second gear wheel (14) of larger diameter, mounted on saidcasing (10) and meshed with said first gear (13), a rod (15) linked atone end to said crank (16), and a double pulley (18) mounted on the freeend (19) of said rod and reciprocating therewith.
 2. The motor drivenapparatus for cleaning the spaces between teeth of claim 1, wherein saidset of stationary pulleys comprises a first pulley (20) mounted on saidouter casing (10) facing said reciprocating double pulley (18) and apair of identical pulleys (21A, 21B) mounted on the sides of an opening(23) formed on the head (22) of said outer casing (10) between whichpulleys (21A, 21B) said operating length (33) of the dental floss (FL)is stretched.
 3. The motor-driven apparatus for cleaning the spacesbetween teeth of claim 2, wherein said second gear wheel (14) and saidtake-up reel (25) are integral with each other, thus forming an unitaryassembly (14, 25) and said feeding reel (24) is mounted on the axis ofsaid unitary assembly and concentrically therewith with theinterposition of a clutch device (38).
 4. The motor-driven apparatus forcleaning the spaces between teeth of claim 3, wherein the reciprocatingmovement of said operating length (33) of dental floss is due to thealternate variation of the length of a first loop of dental flosscomprising the length (30, 31) of floss comprised between the feedingreel (24) and the double pulley (18) and passing around said firststationary pulley (20), and a second loop of dental floss comprising thelength (34, 35) of floss comprised between one (21B) of said pair ofstationary pulleys and said take-up reel (25) and passing around saiddouble pulley (18).
 5. The motor-driven apparatus for cleaning thespaces between teeth of claim 4, wherein rotation of said small gearwheel (13) causes said larger gear wheel (14) also to rotate togetherwith said take-up reel (25) that, accordingly, pulls dental floss (FL)in one direction with a greater force than the force opposed by saidfeeding reel (24) owing to the differential rotating movement thereofallowed by said clutch device interposed between said feeding reel (24)and said take-up reel (25) concentrically mounted.
 6. The motor-drivenapparatus for cleaning the spaces between teeth of claim 5, wherein saidclutch device (38) comprises a disc of a friction felt (42) having thesame diameter of said feeding reel (24).
 7. The motor-driven apparatusfor cleaning the spaces between teeth of claim 5, wherein said casing(110) and said handle (140) are separable, said casing (110) being ofthe disposable type and said handle (140) includes said electrical motor(111) and relative cells.